Telephone system



Jdne 10, 1941.

A. w. HORTON, JR

TELEPHONE SYSTEM Filed Sept. 211939 2 Sheets-Sheet V1 y mno/WOM JR.

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TTOAWEV A. w. HoRrroN, JR

TE ONE SYST /NvENroR A. W HORTOM JR.

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Arron/ver Patented June 10, 1941 TELEPHONE SYSTEM Arthur Horton, Jr., South Orange, N. J., assignor to Bell Telephone Laboratories, Incorpox-ated, New York, Y., a corporation of New York `ApplicationSeptember 21, 1939, Serial No. 295,889

Claims.

This invention relates to telephone systems and more particularly to those systems in which the numerical indication of a calling lineis am tomatically supplied.

It is well known that in certain types of telephone connections such as those, for instance, in which the calling line is extended automatically or otherwise tosome remote station, itis necessary to ascertain the number of the calling station in order that charges for the call may be properly assessed to the station. Such connections are known as toll or long distanceconnections and in manual telephony the calling line is routed to its destination via the position of a recording operator where the number of the calling station is verified over a so-called checking multiple after the number has been communicated to the operator by the calling subscriber. This verificationV is accomplished by touching the tip of a so-called checking cord to a pin in the checking multiple that is individual to the given number, and ifthe number as given is correct,` a tone circuit is` completed over-the checking cord which is heard bytheV operator in her telephone set, thereby verifying the accuracy of the number. On the other hand, if the number is not correct, that is, if the tip of the cord is touched to a pin other thanthat belonging to the calling line, the tone circuit isnot completed, which indicates to the operator that the number given by the subscriber does not correspond to that of the station from which he is calling and service, therefore, will be denied until the discrepancy is rectied.

In automatic telephone systems it is desirable to have the identity of the calling station transmitted automatically to some point at which it may be recorded on settable registers for'visual display of the number by the verifying operator, if the call is to be completed therethrough, or for automatic recording if the information usually obtained by the verifying operator is to berobtained automatically by printing devices responsive to the. settings of registers.

The principal feature of my invention is a coordinate arrangement of rectiers to the crosspoints of each of which the identifying conductor of one of the several lines in the ollce is disposed for corresponding line number identification. Each row and column to which thedifferent horizontal and vertical rectiers belong terminates in a relay connected to one terminus of a source of potential, and the application of the other terminus of this source of potential to the identifying conductor of any line causesthe operation of the vertical and horizontal relays defined by the cross-point to which said conductor is connected. The operation of these two relays may then be utilized to control registers, lamps or other means for displaying or recording the number.

A clearer conception of the scope and purpose of the invention may be obtained from the following description, appended claims and attached drawings in which:

Fig. 1 shows an arrangement of 100 automatic subscribers lines with switching means for extending any of said lines to an operators position, and a lamp indicator at the position; and

Fig. 2 shows the coordinate arrangement of rectiers together with horizontal and vertical relays arranged for operation to identify any` line in a one-hundred line group.

Referring, now, first to Fig. 2, it will be seen that the identifying circuit comprises a coordinate network of cross-points each made .up of two unidirectional impedances of any suitable type but preferably of well-known copper-oxide rectifiers joined at one point and poled to pass current either away from or into the point of connection; and that, for the identification of each of the lines in a one-hundred line group, for example, each impedance of the pair is connected to each of the other impedances in a horizontal row of vertical column which is disposed for the passage of current in an identical direction. Each row of impedances is connected tothe winding of a .horizontal relay and each column of impedances is connected to the winding of a vertical relay and a relay in a row -and another relay in a column, when operated in the manner described hereinafter, will mark a. particular cross-point. Thus, in a network of the above type for the identification of each .of the linesin a one-hundred line group, there would be ten horizontal relays Htl-H9 and ten vertical relays VU-VB through the contacts of which may be controlled a lamp circuit (as shown in Fig. l) or a register or a printer, depending upon the manner and form in which the calling line indication is desired. Since lamp indicators, registers and printers, and the manner in which they can be respectively controlled through settable relays are all well known in the electrical arts, a lamp indicator |00 is shown as typical of all, it being understood that the invention is not limited to a lamp indicator but encompasses any known means of indicating and recording that can be controlled through settable relays.

In Fig. l three subscribers lines of a one-'hunresistance, with the correspondingly numbered impedance cross-point reserved for thelne in the identication circuit of Fig. 2. 'Ihus the sleeve terminal of line Oil isl joined to impedance cross-point 90 by conductor |00 connected to re'- sistance 299; that of line 23 to the impedance' cross-point 23 by .conductor |23 that connects with resistance 223; and that of line 99 to impedance cross-point 99 by conductor |99 that connects with resistance 299. sleeve terminal of each of the other lines in the group is connected by its own conductor to the corresponding cross-point in the network of the identiiicationv circuit.

Now when a call is initiated on any one of the lines, say line 23 for example, for connection with the operators position, said line is extended to an operators trunk l5! over suitable switching facilities |92 guided into Aselective position between the line terminals and those ofthe trunk by the impulses produced through the manipulation ofthe calling dial |03. The extension of the line to the trunk causes a signal (not shown) to be given. at the position which indicates to the operator that service is desired on the trunk,

whereupon information is solicited from the sub.

scriber with respect to the wanted designation .by the Iconnection of a telephone cord |94 to the trunk, said cord being provided with a suitable telephone circuit ||6over which the operator obtains the desired information, and a controllable source of potential |95 which may be applied to the sleeve of the connection. When the operator desires to verify the identity of Vthe calling line as given to her by the callingsubscriber, said source of potential |05 is applied to the sleeve |91 of the trunk jack. Assuming that the source of potential is a battery having its negative pole grounded, the application of said source of potential to the sleeve of trunk jack IDI will establish a current ow from the positive pole of said battery, sleeve of the cord, sleeve |91 of the trunk jack, sleeve of the switching equipment intermediate said trunk jack and ,the` terminals of the calling line, conductor |23, resistance 22.3, through the left-hand impedance, conductor. 393, winding of relay V3 to ground and, through the right-hand impedance, conductor 320, winding of relay H2 to ground. Both relays operate in the circuits above traced, the former .closing an obvious current path for lamp 3 in the units column of lamps andthe latter closing an obvious current path for lamp 2 in the tens column of lamps. Both of these lamps, by `lighting, apprise the operator oi the fact that the calling line number is 23. If Vthe source Aof potential |05 is alternating, the same operations will take place except that no current will ow on that portion of the cycle opposed to the current flow direction of the several impedances in the network. However, by using an alternating source of a suitable frequency or by using relays having slow-release characteristics, the pulsations of the current will not affect the operated relays or the circuits controlled thereover;

In the same way'theV dred line group, namely line 09, line 23 and line In the same way the extension of any line Vin the group to a trunk terminating in a jack at the operators position provides the operator with facilities for ascertaining the line number through operations similar to those above indicated.

It will be noted that, due to the nature of a unidirectional impedance in not offering an innite impedance to the ilow of current in one of its directions, there will be some flow of current through the rectiiers of the row and column marked by the cross-point to which the potential is applied and thence to ground through each of the vertical and horizontal relays in all the rows and columns. This will have a tendency to operate all the relays besides the ones marking the desired cross-point. However, by the suitable selection of a comparatively high resistance for the cross-point itself, this shunting current can be kept down to negligible proportions, and by adjusting the relays to operate on a current above Vthe maximum shunting current, false operations will be avoided.

While this embodiment of the invention has been described with reference to a line groupV of lines and to provide a visual display ofthe calling line number, it is evident that the coodinate disposition of the rectier pairs can be expanded' by any multiple of 100 lines, in which event Vthe .vertical and horizontal relays operated to designate the cross-point of the calling lineI may each be arranged to give the appropriate digital designation in terms of the rows or columns in which the cross-point appears. Further, it is also evident that while the relays are shown as closing lampcircuits to provide visual designations, they can be similarly used to control registers or printer magnets in the wellknown manner in the event it is desired to obtain a permanent record of the calling line.

What is claimed is:

1. An identiiication circuit for the lines of a telephone system comprising in combination a plurality of current responsive devices and a net# work of impedance cross-points in which each cross-point identifies a particular line and through Which'a potentialV applied to any cross# point produces a current flow through the impedance of said cross-point, whereby said plurality of devices are operated to identify the line corresponding to the cross-point to which the potential was applied.

2. An identication circuit for the lines of a telephone system comprising in combination a plurality of current responsive devices and a net* work of impedance cross-points disposed in coordinate pattern in Vwhich each cross-point identies a particular line according to its numerical designation and through which a potential applied t o any cross-point produces a current flow through the impedance of said crosspoint but not operatively through that of any other, whereby certain of said plurality of devices are operated vto identify the numerical designation of the line corresponding to the cross-point to which thel potential was applied.

3. In a telephone system, a calling line identification circuit comprising, in combination with a group of line lterminals, a source of potential connectedgto one of said terminals, a plurality of current responsive devices, and a rectiiier network connected to said terminals and to said devices whereby a current path is established from said source of potential through two of said electroresponsive devices lfor operating said devices to identify the terminal to which said source of potential is connected.

4. An identification circuit for the lines of a telephone system comprising a plurality of unidirectional lcurrent conducting devices arranged in pairs to form rows and columns indicative of the digital designations of said lines, a conductor extending from each of said lines to each of said pairs of devices, and means responsive to the application o! a potential to any one of said conductors for indicating the numerical identity of the line to the conductor of which the potential was applied.

5. An identi-cation circuit for the lines of a ltelephone system comprising a plurality of cop` vper-oxide rectiers arranged in pairs to forni rows and columns indicative of the digital designations of said lines, a conductor extending from each of said lines to each of said paired copperoxide rectifiers in accordance with the designation of the line, and relay means operatively responsive to the application of a potential to any one of said conductors for indicating the numerical identity of the line to the conductor of which the potential Was applied.

ARTHUR W. HOR'I'ON. JR. 

